A grieving mother says not knowing how her two-year-old son died has been a nightmare for his family.
Emily Horan has appealed for anyone with information about Connor's death to contact police.
"We really, really need to get to the bottom of this," Ms Horan said on Tuesday.
Connor died from multiple head and internal injuries at the Warwick Base Hospital at 11.30am on Sunday, August 19, 2018.
Police were told the little boy had fallen down a small set of stairs.
He was in the care of a babysitter at the time.
Connor's tearful grandmother Deborah Ballard says her family misses the beautiful boy and the "happy dance" he used to do.
"We just need to know what happened to my grandson," she said. "Please, anybody out there, please, please come forward with information."
Ms Ballard said that not knowing what had happened to Connor had destroyed her family.
Child trauma detectives are conducting a full investigation into Connor's death, promising to find out exactly what happened before he was taken to hospital.
"We are committed to providing the child's family with the answers they deserve following such a tragic event," Detective Acting Inspector Matt Howard said on Tuesday.
"Detectives are piecing together a timeline of events from that weekend and are seeking the assistance of the public to help us fully understand the circumstances of what happened."
The little boy had been staying with the 38-year-old babysitter at her East Street residence since the Friday before he died.
Detectives want to hear from anyone who was in the Warwick area at the time and saw Connor, or has any information about what happened on that weekend.
Post-mortem results are among the evidence being considered by officers from the Child Trauma Unit and the Darling Downs District Crime Group.
Australian Associated Press
